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  1. #1
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    R404A Pressure-Enthalpy Diagram Properties VS Pressure-Temp Chart Properties



    Hey guys, I need some clarification between these 2 data sets.

    I was studying a refrigeration system that uses R404A. I graphed the refrigeration cycle on a P-H Diagram to get a better idea of what was going on. After that, i looked up a Pressure-Temp Chart for R404 and noticed things were not adding up. On the PH Diagram R404 is at 0*F at a pressure of about 50psia, however according the Pressure-Temp Chart for the same refrigerant, @ 0*F P=33.5 psig. Am i missing something here?

    Thanks in advance!



  2. #2
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    Re: R404A Pressure-Enthalpy Diagram Properties VS Pressure-Temp Chart Properties

    Only missing about 2.5 psi so not too bad.
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    Re: R404A Pressure-Enthalpy Diagram Properties VS Pressure-Temp Chart Properties

    haha actually it turns out it was a little more than 2.5, more like 14.7 psi. I think i have found the discrepancy and it all boiled down to units. The Pressure-Temp table is in psig and the P-H graph is in psia.

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    Re: R404A Pressure-Enthalpy Diagram Properties VS Pressure-Temp Chart Properties

    Quote Originally Posted by milen_d View Post
    haha actually it turns out it was a little more than 2.5, more like 14.7 psi. I think i have found the discrepancy and it all boiled down to units. The Pressure-Temp table is in psig and the P-H graph is in psia.
    Exactly hence my answer.
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    Re: R404A Pressure-Enthalpy Diagram Properties VS Pressure-Temp Chart Properties

    .



    pH charts are always in absolute.
    So they will always be 1 atmosphere
    higher than gauge.

    1 atmosphere = 1 bar = 14.7 psi

    Rob

    .
    .. ... -. .----. - / -- --- .-. ... . / -.-. --- -.. . / --. --- --- -..

  6. #6
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    Re: R404A Pressure-Enthalpy Diagram Properties VS Pressure-Temp Chart Properties

    Cool thanks for the help guys! Just one more example of why units are our friends !

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